The present invention particularly relates to an improvement in the system presenting being marketed by the Gambro Group, to which the assignee of the present application belongs, under the description "Gambro AK-10".
Various details of this system form the subject of, for example, U.S. Pat. Nos. 4,122,010; 4,158,034; 4,293,409; 4,194,974; and 4,191,359; and the descriptions of this system set forth therein are incorporated herein by reference thereto, as are the further improvements thereon disclosed in European patent application No. 84.112914, and the invention according to British Pat. No. 2,003,274, and European patent application No. EP 0 106 940, which are also incorporated herein by reference thereto. Reference is also made to EP No. 0 022 922, which describes in more detail the preparation of dialysis fluid from two concentrates, a preparation which is only touched upon in the following description of the present invention.
Finally, reference is made to U.S. Pat. No. 3,738,382, which describes a different system for the preparation of dialysis fluid in which sterilization is achieved by means of a heating element which is normally included in the system, while at the same time heated sterilizing agent is recirculated through the system in its entirety. Such a system is thus subject to the disadvantage, among other things, that the sterilizing fluid is recirculated through both the less contaminated as well as the more contaminated portions of the system. As a result, impurities may be passed from the more contaminated portions to the less contaminated portions of the system. Furthermore, known systems are designed to operate at pressures above atmospheric pressure, which is applicable only to very unique procedures for the preparation of dialysis fluid, and as a result its applicability is rather limited.